There are a number of different types of machinery that generally act to continuously wind a web material, such as thin plastic films (e.g., thin polypropylene films) as well as paper, paperboard and other type of web materials, after the web material has been processed in a predetermined manner. This type of machinery is available for use in an automated line environment where it is desired to continuously wind the web material.
Most often, the winder is one of the last pieces of equipment in the line where the resulting product is wound around a core or the like for storage, transportation, etc., and therefore, the winder typically follows an oven or the like where the web material, including any coatings thereof, and any other layers are processed to form the resulting product. Because the web material is advanced from one station to the next station, it is important that there are no delays or disruptions in the entire process. For example, if the winder machine has to be taken off line, the upstream web material may be kept in the oven too long and this can lead to direct damage of the web material and even destruction of the web material so that it has to be entirely discarded. Thus, it is desirable that the winder machine have the capability to operate continuously and as individual rolls are formed, there is as near seamless of a transition from a completed roll to an empty core which receives a leading edge of the web material.
In the continuous winding of these web materials, it is very important to maintain control over the tension in the web material throughout as much as possible of the winding process, and particularly, during the change of a full roll to a new core that receives the web material. One of the disadvantages of this type of process and the winding device is that the tension that is applied to the outer wraps of the roll is insufficient to exclude air from being drawn in between the outer wraps, especially during the roll changing motion, air is drawn into the space between the outer wraps and becomes entrapped between the wraps. This air entrapment between the outer web wraps produces wrinkles, bunching, telescoping or skewing in the outermost portion of the roll. As the winding roll is driven to wrap the web material, air is drawn around the rotating winding roll and at the point where the web material contacts the outermost wrap and itself becomes the next outermost wrap, a pressure condition exists and results in air being drawn into this space between the web material and the outermost wrap.
One type of web winder apparatus is a continuous turret-type winder. Turret-type winders have commonly been used with roll changers or accumulators by which each of a pair of core-supporting spindles, which are disposed at ends of the turret arms, are sequentially loaded with a core. A freshly cut leading edge of the web material is attached to the core by any number of suitable devices, such as a roller device. At a particular point in the winding action, the winding roll is indexed about 180 degrees to deliver a fresh core on the recently unloaded spindle of the turret arms to the web transfer station and to deliver the winding roll to an unloading station while the winding continues.
In a continuous winding operation, especially on turret-type winders and particularly for certain kinds of web materials, there are a number of considerations that need to be taken into account in order to produce a uniformly wound roll that is free of defects. One of the foremost considerations to take into account on a turret-type winder is the above-mentioned problem of air entrapment. In order to combat this from happening, it has become relatively common place to provide a pressure roll positioned against the winding roll to control the winding process and eliminate or substantially eliminate the aforementioned problem. More specifically, the pressure roll acts to expel the air layer at the incoming web and prevent this air from being trapped between successive layers. However, the operation of such a roll is complicated in a turret winder as a result of the normal action of the device during and following indexing of the winding roll since during this action, the winding roll moves away from the pressure roll. As a result, air is permitted to enter between the web material layers and this results in the aforementioned problem of slippage between the layers.
Several solutions of this problem have been proposed including the continuous pressure roll winder disclosed in U.S. Pat. No. 4,431,140. This device includes pivotally mounted pressure rolls which contact the cores and the winding roll throughout the entire winding process and throughout the indexing of the turret arms from a core loading station to a roll unloading station while maintaining the relative geometry of contact such that the web contacts the pressure roll at or before contacting the winding roll.
While the device disclosed in the '140 patent solves some problems associated with previous winding devices, the '140 device still suffers from disadvantages. More specifically, the '140 device is constructed such that the turret arm are rotated to a first position to permit a full roll to be removed from the device, at generally the nine o'clock position, while the new core winds at a three o'clock position as shown in the Figures of the '140 patent. The three o'clock position is also the position where the cutting mechanism along with other complex mechanisms are located and therefore, the three o'clock position is fairly crowded. In the '140 device, after the finished roll is removed, a new core is not inserted at the nine o'clock position since if a new core was inserted here, the rotation of the turret arm in the clockwise direction to place the current winding roll in the nine o'clock unloading direction would result in interference between the new core and the web material as it is fed along rollers and the like to the pack roll assembly, etc. and then onto the winding roll. As will be appreciated by viewing the figures of the '140 patent, the clockwise rotation of the turret arm would cause a new core inserted at the nine o'clock position to fold over onto the web as it is being fed to the pack assembly. In other words, the location and action of the web material prevents the rotation of the winding roll to the unloading location since the new core can not pass through the web material that is trained across rollers and the like.
Instead, the '140 device has to be operated such that the full completed core is removed from the nine o'clock position as the new core winds in the three o'clock position; however, a new core can not be inserted at the unloading location (nine o'clock position) for the reasons stated above. The new core has to be inserted at the three o'clock position after the turret arm is rotated so that the winding roll moves from the three o'clock position to the nine o'clock position. In other words, the new core can not be loaded at the same location where the old finished core is unloaded. One of the disadvantages of this type of scheme is that the three o'clock position in the '140 device is not that accessible due to the presence of other equipment, such as the cutting devices, and therefore it is not easy for a core loader to be disposed at this location. Furthermore, this type of arrangement where the finished core is unloaded at one location and a new core is inserted at another location requires multiple pieces of equipment at two locations to complete these tasks. In other words, unloading equipment is located near the unloading location and loading equipment is located near the loading location. Accordingly, the same equipment can not be used to perform both the unloading and loading operations and this greatly increases the complexity of the design and increases crowding of the various components and reduces accessibility at different locations.
What has heretofore not been available is a continuous winder that permits pressure to be applied to a winding roll at a point of entry of the web throughout the entire winding cycle and also permits a new core to be immediately inserted at the same location where a finished roll was just removed while the winding of a new roll continues at another location. In addition, it is desirable for this same device to allow for the pack rolls to be run in a gap position with a minimal distance being maintained between the roll and the building winding roll.